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Abstract:

A heat exchanger apparatus containing a heat exchanger and a thermally
actuated bypass valve. The heat exchanger having plurality of plates
defining a first, a second and a bypass channels. A first fluid inlet
manifold in fluid communication with the first and the bypass channels.
The bypass valve positioned in the first fluid inlet manifold, and
containing a sleeve having a first slot and a second slot, that permit
fluid flow from a first fluid inlet to the bypass channel and to the
first fluid inlet manifold, respectively. A drum positioned within the
sleeve and movable from a first position to a second position. The drum
having an aperture permitting first fluid flow to the first slot in the
first position and to the second slot in the second position. An actuator
engaging the drum and actuating it to move from the first position to the
second position.

Claims:

1. A heat exchanger apparatus comprising: a heat exchanger, comprising a
plurality of plates defining a first fluid channel, a second fluid
channel and a bypass channel; first fluid inlet and outlet manifolds
having first fluid inlet and outlet, respectively, the first fluid inlet
and outlet manifolds being in fluid communication with the first fluid
channel; and, the first fluid inlet manifold also being in fluid
communication with the bypass channel; and a thermal bypass valve
positioned in the first fluid inlet manifold, the thermal bypass valve
comprising: a sleeve having a first slot and a second slot, the first
slot permitting fluid flow from the first fluid inlet to the bypass
channel, and the second slot permitting fluid flow from the first fluid
inlet to the first fluid inlet manifold; a drum positioned within the
sleeve and slidably movable from a first position to a second position,
the drum having a first aperture and one or more additional apertures,
the first aperture in fluid communication with the first fluid inlet and
the one or more additional apertures directing fluid to the first slot or
the second slot in the first or second position; and a thermal actuator
engaging the drum and actuating the drum to move from the first position
to the second position in response to the temperature of the first fluid.

2. The heat exchanger apparatus of claim 1, wherein the one or more
additional apertures comprises a second aperture, and the second aperture
permitting first fluid flow to the first slot in the first position and
to the second slot in the second position.

3. The heat exchanger apparatus of claim 1, wherein the one or more
additional apertures comprises a second aperture and a third aperture,
wherein in the first position, the second aperture permitting first fluid
flow to the second slot and the drum preventing flow to the first slot,
and in the second position, the third aperture permitting first fluid
flow to the first slot and the drum preventing flow to the second slot.

4. The heat exchanger apparatus according to claim 1, further comprising
a fitting at the first fluid inlet, and wherein the sleeve further
comprises a lip positioned between the fitting and the first fluid inlet
for affixing the sleeve in position.

5. The heat exchanger according to claim 1, wherein the actuator is
coupled to the fitting.

6. The heat exchanger according to claim 1, wherein the actuator
comprises a motor containing a thermally expandable contractable material
coupled to a piston.

7. The heat exchanger according to claim 6, wherein the piston engages
the drum and moves from a first piston position to a second piston
position and back to the first piston position in response to the thermal
expansion and contraction of the thermally expandable contractable
material.

8. The heat exchanger according to claim 6, wherein the thermally
expandable contractable material is wax.

9. The heat exchanger according to claim 1, further comprising a biasing
means for biasing the drum in the first position.

10. The heat exchanger according to claim 9, wherein the biasing means is
a spring.

11. The heat exchanger according to claim 1, wherein an end of the drum
has an arcuate profile for operatively coupling the drum to the thermal
actuator.

12. A thermal bypass valve, comprising: a sleeve having a first slot and
a second slot; a drum positioned within the sleeve and slidably movable
from a first position to a second position, the drum having a first
aperture and one or more additional apertures, the first aperture in
fluid communication with a first fluid inlet and the one or more
additional apertures directing fluid to the first slot or the second slot
in the first or second position; and a thermal actuator engaging the drum
and actuating the drum to move from the first position to the second
position in response to the temperature of a first fluid.

13. The thermal bypass valve of claim 12, wherein the one or more
additional apertures comprises a second aperture, and the second aperture
permitting first fluid flow to the first slot in the first position and
to the second slot in the second position.

14. The thermal bypass valve of claim 12, wherein the one or more
additional apertures comprises a second aperture and a third aperture,
wherein in the first position, the second aperture permitting first fluid
flow to the second slot and the drum preventing flow to the first slot,
and in the second position, the third aperture permitting first fluid
flow to the first slot and the drum preventing flow to the second slot.

15. The thermal bypass valve according to claim 12, further comprising a
lip for affixing the sleeve in position.

16. The thermal bypass valve according to claim 12, wherein the actuator
comprises a motor containing a thermally expandable contractable material
coupled to a piston.

17. The thermal bypass valve according to claim 16, wherein the piston
engages the drum and moves from a first piston position to a second
piston position and back to the first piston position in response to the
thermal expansion and contraction of the thermally expandable
contractable material.

19. The thermal bypass valve according to claim 12, wherein an end of the
drum has an arcuate profile for operatively coupling the drum to the
thermal actuator.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S.
Provisional patent application No. 61/579,313, filed Dec. 22, 2011. The
content of the above-noted patent application is hereby expressly
incorporated by reference into the detailed description hereof.

FIELD OF THE INVENTION

[0002] The specification relates to a heat exchanger apparatus having an
integrated thermal bypass valve (TBV).

BACKGROUND OF THE INVENTION

[0003] Heat exchanger systems that vary the path of fluid flowing through
the heat exchanger in response to a change in the characteristics (e.g.
temperature, pressure, etc.) of the fluid are known. For example, WO
94/29659 shows a plate-type oil cooler which has a pressure-responsive
valve assembly connected to the inlet of the oil-side to permit the oil
to bypass the oil-side of the cooler when the pressure on the oil-side of
the cooler exceeds a predetermined value. Alternatively, U.S. Pat. No.
4,669,532 discloses a bimetallic valve which is disposed in the oil-side
of an oil-cooler to permit the oil to bypass the oil-side of the cooler
when the temperature of the oil is below a predetermined value.

[0004] Additionally, there are numerous examples of heat exchanger systems
wherein the flow rate of a fluid flowing through a heat exchanger is
controlled according to the temperature of that of another fluid flowing
through the heat exchanger. For example, German Laid-Open Application No.
196 37 818 and European Laid-Open Application No. 787 929 show two such
systems wherein the flow of coolant through an oil cooler is controlled
in response to the temperature of the oil flowing through the heat
exchanger. In both of the systems, a thermostat is located upstream of
the inlet to measure the oil temperature before the oil enters the heat
exchanger, although it is also known to control the flow of coolant
through the heat exchanger system in response to the oil temperature as
it exits the heat exchanger.

[0005] The problem with these systems is that they may take up
considerable amounts of space, which is always at a premium in automotive
applications, a primary use of this art. Additionally, these systems may
add weight to the vehicle to which they are attached, possibly degrading
fuel economy thereby. Furthermore, the environment surrounding the
thermostat in these systems may affect the oil temperature reading,
causing more or less coolant to be directed to the heat exchanger than is
actually necessary.

SUMMARY OF THE INVENTION

[0006] According to one aspect of the present application, there is
provided a heat exchanger apparatus containing:

[0007] a heat exchanger, containing

[0008] a plurality of plates
defining a first fluid channel, a second fluid channel and a bypass
channel;

[0009] first fluid inlet and outlet manifolds having first fluid
inlet and outlet, respectively, the first fluid inlet and outlet
manifolds being in fluid communication with the first fluid channel; and,
the first fluid inlet manifold also being in fluid communication with the
bypass channel; and

[0011] a sleeve having a
first slot and a second slot, the first slot permitting fluid flow from
the first fluid inlet to the bypass channel, and the second slot
permitting fluid flow from the first fluid inlet to the first fluid inlet
manifold;

[0012] a drum positioned within the sleeve and slidably movable
from a first position to a second position, the drum having a first
aperture and one or more additional apertures, the first aperture in
fluid communication with the first fluid inlet and the one or more
additional apertures directing fluid to the first slot or the second slot
in the first or second position; and

[0013] a thermal actuator engaging
the drum and actuating the drum to move from the first position to the
second position in response to the temperature of the first fluid.

[0014] According to another aspect of the present application, there is
provided a thermal bypass valve containing:

[0015] a sleeve having a first slot and a second slot;

[0016] a drum positioned within the sleeve and slidably movable from a
first position to a second position, the drum having a first aperture and
one or more additional apertures, the first aperture in fluid
communication with a first fluid inlet and the one or more additional
apertures directing fluid to the first slot or the second slot in the
first or second position; and

[0017] a thermal actuator engaging the drum and actuating the drum to move
from the first position to the second position in response to the
temperature of a first fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 shows a cross-section of a portion of an oil-to-water (OTW)
heater with an internally mounted thermal bypass valve (TBV) in the hot
(i.e., oil hotter than the valve actuation set point temperature)
condition, with oil flowing through the bypass channel;

[0019] FIG. 2 shows the OTW heater of FIG. 1 in the cold (oil colder than
valve set point temperature) condition, with oil flowing through the heat
exchanger;

[0020] FIG. 3 shows a cross-section of a portion of an OTW cooler with an
internally mounted TBV in the hot condition, with oil flowing through the
heat exchanger;

[0021] FIG. 4 shows the OTW cooler of FIG. 3 in the cold condition, with
oil flowing through the bypass channel; and

[0022] FIG. 5 shows a plan view of a thermal bypass valve in accordance
with one embodiment, for use in a OTW cooler, with the drum in the first
position.

[0023] FIG. 6 shows a thermal bypass valve in accordance with an
embodiment, for use in a OTW cooler, with the drum in the first position.

[0024] FIG. 7 shows the sleeve and drum of a thermal bypass valve in
accordance with an embodiment shown in FIG. 6.

DESCRIPTION

[0025] The present description discloses, as an embodiment, a heat
exchanger apparatus having a heat exchanger and a thermally actuated
bypass valve positioned within the heat exchanger.

[0026] An oil-to-water (OTW) heat exchanger, where a water-based heat
exchange fluid such as engine coolant, is used to heat or cool oil. When
combined with a suitable valve as disclosed herein, an OTW heat exchanger
can be used either as an oil cooler, or oil warmer. In an OTW cooler
configuration, where heat is transferred from the oil to the coolant, the
oil flows through the heat exchanger in the hot state and bypasses the
heat exchanger in the cold state. In an OTW heater configuration, where
heat is transferred from the coolant to the oil, the oil flows through
the heat exchanger in the cold state and bypasses the heat exchanger in
the hot state. An OTW heater can help to accomplish rapid warm-up of the
oil from a cold start condition, knowing that the engine coolant heats up
more quickly than the oil.

[0027] In accordance with the embodiment of the present specification, the
thermally actuated bypass valve (TBV) is internally mounted within the
heat exchanger, and which can help to reduce the overall amount of space
required by the heat exchanger apparatus. In a further embodiment in
accordance with the specification, the heat exchanger apparatus includes
a TBV mounted in an oil inlet fitting and/or oil inlet manifold of the
heat exchanger.

[0028] The embodiments in accordance with the specification will now be
described with reference to the figures. FIGS. 1 and 2 show a
cross-section of a portion of an OTW heater 10 containing a core 12 made
up of a plurality of dished heat exchanger plates. The type of plates
used is not particularly limited and provide for a first fluid channel, a
second fluid channel and a bypass channel 38. For instance, and as
disclosed in the embodiments in FIGS. 1 to 4, the first and second fluid
channels are formed by a plurality of nested dish plates, which in one
embodiment can be identical. The first fluid channel, as disclosed
herein, can provide a passage for flow of oil, while the second fluid
channel can provide a passage for flow of a coolant or other liquid, for
heat exchange. The bypass channel 38, as disclosed herein, can be formed
by a generally flat plate 40 positioned above the nested dish plates and
a bypass channel cover plate 18. The bottom of the heater 10 can be
provided with another nested flat bottom dish plate 42 to enclose the
heater 10.

[0029] In one embodiment, the heater 10 can be provided with inlet and
outlet manifolds for both the coolant and oil, but only the oil inlet
manifold 14 is shown in the drawings herein. The oil inlet manifold 14
and oil outlet manifold are in fluid communication with oil flow passages
in core 12 for flow of the first fluid. While the coolant inlet manifold
and coolant outlet manifold (not shown) are fluid communication with the
second channel, permitting flow of the coolant. In the embodiment
disclosed, the manifold 14 is closed at its bottom and receives oil
through its upper end from an oil inlet 44, to which can be coupled an
oil inlet fitting 16. The fitting 16 is attached to the top of a bypass
channel cover plate 18, and is provided with an opening for the oil
entry. As disclosed herein, in one embodiment, the bypass cover plate 18
may cover the entire top of the core 12.

[0030] In the embodiment disclosed, the bypass channel 38 is present above
the dished heat exchanger plates and close to the oil inlet fitting 16.
However, the bypass channel 38 could also be positioned, for example and
without limitation, below the core 12 of the heat exchanger plates with
the fitting 16 attached to a top plate of the dished heat exchanger
plates.

[0031] Received inside the oil inlet fitting 16 and the oil inlet manifold
14 is a thermal bypass valve (TBV) 19 having an outer sleeve 20,
generally in the form of a cylinder. The outer sleeve 20 is closed at its
bottom end 46, which is further away from the oil inlet 44 or can be open
and provided with a flange extension for retaining a biasing means, as
explained further herein and as shown in the figures. In one embodiment
and as disclosed in the figures, a major portion of the thermal bypass
valve is retained in position within the oil inlet manifold 14. In a
further embodiment, the top of sleeve 20 has a lip 22 which is retained
between the fitting 16 and cover plate 18, for affixing the sleeve 20 and
the TBV 19 in place in the oil inlet manifold 14. The outer sleeve 20 is
provided with upper slots 24 (or first slot) (encircled in FIGS. 1-4 and
7) and lower slots 26 (or second slot) (encircled in FIGS. 1-4, 6 and 7)
for reasons which will become apparent below. The slotted outer sleeve 20
is more clearly shown in FIGS. 5-7.

[0032] In the embodiment disclosed in the figures, the upper slots 24 of
the sleeve permits fluid flow from the oil inlet 44 to the bypass channel
38. While the lower slots 26 in the sleeve permit fluid flow from the oil
inlet 44 to the oil inlet manifold 14, and from there, entering the core
12 of the dished heat exchanger plates for heat exchange.

[0033] Located inside the outer sleeve 20 is a drum 28 that can slidably
move within the sleeve 20 from a first position (FIGS. 2 and 4) to a
second position (FIGS. 1 and 3). The drum 28 has a first aperture 48
(encircled in FIGS. 1-3) that is in fluid communication with the first
fluid inlet 44 (encircled in FIGS. 1-3) or opening in the oil inlet
fitting 16 to allow the fluid, such as oil, to enter the drum. In
addition, the drum 28 is also provided with one or more apertures 36
(encircled in FIGS. 1-4 and 7), such as a second aperture 52 or a second
52 and third 54 aperture, for reasons which will become apparent below.
The drum 28 is also shown in FIGS. 5 and 6 positioned within the sleeve,
while FIG. 7 shows the drum 28 removed from the sleeve 20. The shape of
the drum 28 is not particularly limited, and in one embodiment, is
generally in the form of a cylinder with a closed bottom, which is away
from the oil inlet. In another embodiment, and as shown in the figures,
the lower or bottom portion 50 of the drum 28 can have a particular
profile, such as an arcuate profile, as described further herein.

[0034] The drum 28 contains a thermal actuator 30 which may be in the form
of a wax motor, and which, in one embodiment, is rigidly mounted at its
upper end to the oil inlet fitting 16. The interior of the actuator 30
contains a wax which expands when heated, such as for example, because of
the temperature of the fluid. The actuator 30 includes a piston 32 which
extends when the wax is heated and can retract when the wax cools.
Therefore the piston 32 is in the extended state in FIG. 1 when the oil
is hot and is in the retracted state in FIG. 2 when the oil is cold.

[0035] The piston 32 engages the drum 28 such that the drum 28 moves
downwardly from a first position (as shown in FIGS. 2 and 4) to a second
position (as shown in FIGS. 1 and 3) when the piston 32 extends. In the
embodiment disclosed, the shape of the bottom of the drum 28 allows it to
be operatively coupled to the piston 32 with the drum 28, such that the
drum 28 moves in response to the piston 32. In the embodiment disclosed
in the figures, the arcuate profile of the bottom of the drum 28 allows
the piston 32 engage the drum 28, to operatively couple the piston 32 to
the drum 28.

[0036] In a further embodiment and as disclosed herein and shown in FIGS.
1 to 4, a biasing means can be provided for biasing the drum 28 towards
the first position. For example, a coil spring 34 between the outer
sleeve 20 and the drum 28 pushes the drum 28 upwardly when the piston 32
retracts.

[0037] As noted above, the drum 28 is also provided with one or more
apertures 36 in addition to the first aperture 48, which is in fluid
communication with the inlet 44. In one embodiment, as shown in FIGS. 1
and 2, the drum 28 can be provided with second 52 and third 54 apertures
(encircled); while in another embodiment, as shown in FIGS. 3, 4, 5 and
7, the drum can be provided with a second 52 aperture (encircled) only.
The second 52 and third 54 apertures (when present) can be provided as a
single opening or as multiple openings. Further, as shown in the figures,
the second 52 and third 54 apertures can be longitudinally aligned with
each other along the length of the drum 28. In an alternative embodiment,
the second 52 and third 54 apertures can be offset (not shown) from each
other along the length of the drum 28, so long as they allow fluid
communication from the drum 28 to the slots of the outer sleeve 20 in
different position of the drum, as disclosed herein.

[0038] In one embodiment of a OTW heater where the drum 28 is provided
with a second 52 and third 54 apertures, with the oil in the cold
condition, as shown in FIG. 2, the piston is retracted and the drum 28 is
raised, so that the drum 28 blocks the upper slots 24 in the outer sleeve
20, and the second aperture 52 in the drum 28 align with the lower slots
26 of the outer sleeve 20. Therefore, a closed flow path is created to
block off bypass passage 38 from the oil inlet fitting 16 to core 12, and
the oil enters the oil inlet manifold 14 through aligned second aperture
52 and slots 26. Therefore the oil enters the manifold 14 and flows
through the heat exchanger core 12, where it is heated by the coolant.

[0039] As the oil temperature increases, the temperature of the actuator
30 increases and the piston 32 extends to the position shown in FIG. 1.
This pushes the drum 28 down so that the second aperture 52 of the drum
28 is blocked by the outer sleeve 20, and the top of the drum 28 no
longer blocks the upper slots 24 in the outer sleeve 20. Therefore, in
this position, the third aperture 54 aligns with the first slot 24 in the
outer sleeve 20 and the hot oil enters the bypass channel 38 between the
cover plate 18 and core 12, and does not enter the inlet manifold 14 of
heat exchanger 10.

[0040] FIGS. 3 and 4 show, as an embodiment, a cross-out section of a
portion of an OTW cooler 10 which has most of the same elements as OTW
heater 10 described above. Like elements of cooler 10 are therefore
described by like reference numerals. One difference in such an
embodiment is that the drum 28 can be provided with only the first 48 and
second 52 (encircled in FIGS. 3 and 4) apertures, with the first aperture
48 in fluid communication with the oil inlet 44 or opening in the oil
inlet fitting 16 to allow oil to enter the drum 28.

[0041] In the hot condition shown in FIG. 3, with the piston 32 extended,
the second aperture 52 of drum 28 is aligned with the lower slots 26 of
outer sleeve 20, and the drum 28 blocks the upper slots 24. Therefore,
the hot oil flows from inlet 44 to manifold 14, and then flows through
core 12 where it transfers heat to the relatively cool coolant.

[0042] In the cold condition shown in FIG. 4, with the piston 32 is in the
retracted position, the second aperture 52 of the drum 28 align with the
upper slots 24 of the outer sleeve 20 to allow the oil to bypass the heat
exchanger core 12. The drum 28 blocks oil flow to manifold 14, and
therefore oil is prevented from flowing through the lower slots 26 of
outer sleeve 20 and into manifold 14.

[0043] While the present invention has been described with reference to
example embodiments and the accompanying drawings, it will be understood
by those skilled in the art that the invention is not limited to the
preferred embodiment and that various modifications could be made thereto
without departing from the scope of the invention as defined by the
claims.